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Intel Mesa Gives Problems With KDE's KWin, Again

04-18-2011, 10:30 AM

Phoronix: Intel Mesa Gives Problems With KDE's KWin, Again

Martin Gräßlin, the lead KDE developer of the KWin compositing window manager, usually has fairly insightful and technical blog posts. Last week he was talking about possibly moving the KDE screensaver into the KWin compositor for KDE SC 4.8 after writing the KDE view on GNOME's new compositing manager. Today he has written a new post, but this time it's about the open-source Intel Mesa driver breaking (again) for KWin...

Instead of talking to driver developers like Wine and Gnome people do and resolving issues together, he prefers writing ranty blog posts where he describes how bloody hacks in KWin are driver developers' fault. Typical coward.

Comment

Still I could talk to them now instead of writing angry blog posts? Sadly I cannot. First of all we were notified about the change too late to do anything. As just explained we were notified after 4.6.2 and no chance to adjust before Natty. Furthermore I was ill last week, are sitting in a plane to the US right now, so I can write blog posts but cannot use Internet and I will stay more or less disconnected throughout the next week.

Comment

Instead of talking to driver developers like Wine and Gnome people do and resolving issues together, he prefers writing ranty blog posts where he describes how bloody hacks in KWin are driver developers' fault. Typical coward.

Oh right, so now it's the kwin developers' fault that the free graphics driver developers fucked up once again?

Comment

I think that Marek was less concerned with passing the blame and more about the approach to resolving problems.

I don't think that checking the renderer string is the correct thing to do, but I also don't know any other way.

It's also quite amazing that the Intel devs broke one of the most important linux apps out there in a point release without even checking whether it works. The solution is to downgrade the driver and use the old one until the issue is resolved, and that's quite pointless.

A simple regression test would have given everyone enough time to find the problem and resolve it.

Comment

What KWin needs to do is whether GL is hardware-accelerated, and there is no way to check that. Even in forums when people debug driver issues, people look at the renderer string.

Martin is a volunteer and has my thanks for all his hard work. He also rants a lot, which is sometimes unfortunate. But the sad fact is that Intel released a driver which broke KWin, one of the most important applications in Linux. They either

- released a driver without even testing whether it works, or
- released a driver although they knew it would break the desktop for many users, and didn't tell anyone.

Comment

I don't know how well that works, but KWin needs OpenGL 2 functionality for some things, so even hardware-accelerated drivers using old codepaths don't work -- that's why they're checking for DRI2. Only Intel does not list DRI2 in the renderer string either, so they tested for GEM, which got removed.

Grepping the renderer string is an old evil which broke many things in the past, even 10 years ago, but there is simply no good way to test what the driver actually supports today, and that's a problem.

With KDE 4.5, KWin made changes which broke things on Mesa drivers and were (rightly) criticised for not testing with open drivers. They said that they trusted the drivers about the functionality they advertised, but didn't implement.

This time, Mesa devs made changes which broke KWin, and KWin guys did not even know about it until it hit Ubuntu repositories.